Photon-tissue interaction model enables quantitative optical analysis of human pancreatic tissues

Abstract

A photon-tissue interaction (PTI) model was developed and employed to analyze 96 pairs of reflectance and fluorescence spectra from freshly excised human pancreatic tissues. For each pair of spectra, the PTI model extracted a cellular nuclear size parameter from the measured reflectance, and the relative contributions of extracellular and intracellular fluorophores to the intrinsic fluorescence. The results suggest that reflectance and fluorescence spectroscopies have the potential to quantitatively distinguish among pancreatic tissue types, including normal pancreatic tissue, pancreatitis, and pancreatic adenocarcinoma.

Characterizing human pancreatic cancer precursor using quantitative tissue optical spectroscopy

“…1), indicating nuclear enlargement both in IPMN and AC relative to normal pancreas. Additionally, the ratio of the extracted nuclear size of AC to normal tissue (11.64/8.89 = 1.30) is consistent with the previously reported nuclear dilation factor L/L 0 (1.27 ± 0.01) [13]. The result for mean extracted refractive index of normal pancreas (1.372) was consistent with previous reports [12,13].…”

“…1. The 22 normal and 33 AC reflectance and fluorescence spectra from 11 and 17 sites, respectively, used for comparison with the IPMN data, were reported previously [13]. For one IPMN patient, fluorescence spectra were not recorded due to misalignment.…”

“…A PTI model for reflectance and fluorescence spectra was reported [12,13]. The model employed a semi-empirical reflectance equation to extract absorption-and scattering-related tissue parameters from measured reflectance spectra.…”

“…The features in the 400-440 nm and 540-580 nm ranges were attributed mainly to hemoglobin absorption. The higher reflectance in the 450-530 nm range in IPMN and AC sites was attributed to the cellular density and nuclear size [12,13]. Figure 2(B) shows wavelength-dependent standard errors of the mean spectra for each tissue type.…”

“…Advantages of optical spectroscopy compared to current imaging modalities (listed above) include quantifying tissue morphological and biochemical alterations occurring at the molecular and cellular levels during neoplastic progression [10] and clinical compatibility with EUS-FNA procedures [11]. Previously, our group successfully distinguished human pancreatic diseases, including pancreatic adenocarcinoma (AC) and chronic pancreatitis, from normal tissues with multimodal optical spectroscopy and a mathematical photon-tissue interaction (PTI) model [12][13][14][15].…”